Managing your Model Railroad Wi-Fi Network How to Build and Manage a Model Railroad Wi-Fi Network using the WifiTrax Products Practical notes by Steve Shrimpton ©Steve Shrimpton 2017 All rights reserved Updated August 5, 2017 to include Direct Wi-Fi Mode Back to Web Site The WifiTrax series of products enable you to use a Wi-Fi Network to connect Hand-Held devices such as smart phones and tablets to your locomotives and other items on your layout equipped with WifiTrax Wi-Fi Controllers. In this document, I will show you first how to set up your WifiTrax network with your first locomotive and then how to manage your network and add more locomotives as you equip more of your locomotives with Wi-Fi Controllers. First, we will need to run over some basics concerning networks and Wi-Fi networks in particular. Related Documents You can obtain these from our website www.wifitrax.com (1) The WifiTrax Model Railroad Network Vision – this will tell you about our concept for an entire model railroad infrastructure based on Wi-Fi and the products that will be released to support it. Tools and Skills Required 1. Basic Computer Literacy 2. A computer with Windows 7, 8, 8.1 or 10 installed or a Surface Pro with Windows 10 3. A smart phone or tablet with Android 4.4 or later, or alternatively the computer in 2. has Windows 10 installed. 4. A Wi-Fi Router 5. There is NO computer programming required. Networking Basics – Three Important Terms Laptop Computer Tablet or Smart Phone Desktop Computer Printer The Internet Figure 1 Typical household network In 2014, it was reported that 73% of U.S households own a computer with a broadband connection to the internet. This means that these households have a network router and a good many will have a Wi-Fi Network Router so that smart phones and tablets can access the internet via the same broadband connection. I bet among model railroaders the percentage is even higher. Why is it called a router? Because it routes packets of data between computers on your local network in your house and also between your local network and the internet. Therefore, most of you already have the infrastructure in place to build your model railroad network. Moreover, that infrastructure can carry a lot of data, so we can imagine all kinds of clever things we can do with our networked model railroads in the near future. Figure 2 shows a typical household network with a desktop computer, a laptop, a network printer and a tablet or smart phone. How does it work? Well, almost anything that connects to networks and the internet is assigned something called an IP-Address. That’s nothing more than a postal address for each computer connected to your router, whether it’s a smart phone, desktop, tablet or a model railway locomotive. That’s the first idea to get clear. Nothing can be on your network unless it has an IP- address, because no one could talk to it! Figure 2 shows an IP address assigned to each item on the network – even the router has its own IP Address (usually 192.168.0.1). IP Addresses are always written as four numbers each 0 to 255 separated by dots e.g. 192.168.0.1, the address of the router mentioned. Laptop Computer Tablet or Smart Phone Desktop Computer Printer MAC Address: 54-27-1E-F4-6A-D6 MAC Address: 32-29-1C-F4-7A-D2 MAC Address: 27-32-3F-D4-72-F6 MAC Address: 2F-B2-3A-D4-82-F9 IP Address: 192.168.0.10 IP Address: 192.168.0.11 IP Address: 192.168.0.15 IP Address: 192.168.0.22 Wi-Fi Connection Wi-Fi Connection Wi-Fi Connection Wi-Fi Connection Wire Connection Wire Connection MAC Address: 00-23-2C-B4-AA-D7 IP Address: 192.168.0.1 MAC Address IP-Address 54-27-1E-F4-6A-D6 192.168.0.10 32-29-1C-F4-7A-D2 192.168.0.11 27-32-3F-D4-72-F6 192.168.0.15 2F-B2-3A-D4-82-F9 192.168.0.22 MAC Address: 59-37-1A-F9-5B-D8 MAC Address: 44-47-1C-A4-6A-B5 59-37-1A-F9-5B-D8 192.168.0.30 IP Address: 192.168.0.30 IP Address: 192.168.0.31 44-47-1C-A4-6A-B5 192.168.0.31 The Internet Figure 2 Typical Network within your Home, with your WifiTrax Model Railroad Locomotives Added. The IP and MAC addresses here are just typical examples. Next question: Where do these IP-Addresses come from? The answer is that your network router assigns them. The network router is in charge of the network. When a new computer connects to your network, it first has to ask the network router for an IP-Address and the network router assigns it one. The network router keeps track of all the IP-Addresses it has assigned and which computer has them. How can the router identify computers before it’s given them an IP-Address? The answer is that every computer has a special identifier that it was born with and which never changes. This is called a MAC Address or sometimes Physical Address and every computer that connects to a network has its own MAC Address, and no two are the same – just like fingerprints. So, when a computer asks for an IP Address from the network router, it sends its MAC Address to the router. The router assigns it an IP Address and adds an entry to a table that it keeps of the IP Address assigned to every MAC Address. So, the router remembers computers on its network according to their MAC Addresses. The three underlined terms above are the ones to remember Network Router, IP Address and MAC Address – we will use these terms a lot. Extra Information If you want to be a bit more technical, the protocol by which this all happens is called DHCP (Dynamic Host Control Protocol), MAC Address stands for Media Access Control and IP is Internet Protocol. Of course I’m keeping it simple. If you want more there’s plenty on the internet. What is this strange IP Address format? Every IP Address is actually a 32-bit binary number (0 to 4,294,967,295 in decimal) so there are more than 4 billion of them available. To make them easy to read they are represented as four decimal numbers each from 0 to 255 representing each 8-bit byte in the 32-bit binary number. So, they look like this: 27.195.67.255, 192.168.1.1, 123.212.233.123 but never 456.256.500.512! None of the four numbers can be bigger than 255 and both 0 and 255 are reserved in the last of the four numbers. Wi-Fi Network Basics – Two More Important Terms So far, I’ve talked about networks. In the old days, we used cables with little RJ-45 connectors to join our computers to the network router. That’s still the fastest way, but now most people use laptops and tablets that connect to the network router via Wi-Fi. Wi-Fi is just another medium on which the data can travel – radio of course – instead of cables. The Wi-Fi network router has an antenna and acts as an Access Point (AP). It’s the master of the Wi-Fi network. All the Wi-Fi computers – laptops, tablets, model locomotives, etc. connected to it are Client Stations – or Stations as they are usually called. Remember the fact that it’s a Wi-Fi network makes no difference as far as IP Addresses and MAC Addresses are concerned. So, the two terms underlined in this section are important to remember – Access Point and Station. More than One Network – SSID and Password Wi-Fi Connection Jack s Laptop Computer MAC Address: 54-27-1E-F4-6A-D6 IP Address: 192.168.0.10 Wi-Fi Connection Jill s Tablet or Smart Phone MAC Address: 32-29-1C-F4-7A-D2 IP Address: 192.168.0.11 MAC Address: 00-23-2C-B4-AA-D7 MAC Address: 20-35-2F-A4-AA-67 IP Address: 192.168.0.1 IP Address: 192.168.0.1 SSID: JacksWiFi SSID: JillsWiFi Password: J@cks123 Password: J!lls321 Figure 3 Two Wi-Fi Networks that overlap in their range What happens if there’s two or more Access Points (AP’s) in the same house? The answer is that they get along just fine. Each one has their own network of clients and assigns them IP-Addresses and they coexist in the amazing radio world just like different radio stations in the same city. For example, when you connect to your Wi-Fi Router’s Access Point in your house, you usually can see a few neighbors’ access points too. How come you don’t connect to them? Well because most people secure their access points with passwords. Now each access point has an identifier called its SSID and it has an assigned password. Figure 3 shows two Wi-Fi networks. Jack and Jill are neighbors and both have Wi-Fi routers, Jack’s network and Jill’s network. Both have SSID’s and passwords. Jack does not know Jill’s password and Jill does not know Jack’s password. When Jack bought his laptop and connected to his Wi-Fi he saw Jill’s network as well as his own but he only knew the password for his own network.